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MDEV-452 Add full support for auto-initialized/updated timestamp and datetime

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Generalized support for auto-updated and/or auto-initialized timestamp
and datetime columns. This patch is a reimplementation of MySQL's
"WL#5874: CURRENT_TIMESTAMP as DEFAULT for DATETIME columns". In order to
ease future merges, this implementation reused few function and variable
names from MySQL's patch, however the implementation is quite different.

TODO:
The only unresolved problem in this patch is the semantics of LOAD DATA for
TIMESTAMP and DATETIME columns in the cases when there are missing or NULL
columns. I couldn't fully comprehend the logic behind MySQL's behavior and
its relationship with their own documentation, so I left the results to be
more consistent with all other LOAD cases.

The problematic test cases can be seen by running the test file function_defaults,
and observing the test case differences. Those were left on purpose for discussion.
This commit is contained in:
unknown
2012-10-17 15:43:56 +03:00
parent 620d14f8c3
commit bc4a456758
61 changed files with 5375 additions and 540 deletions
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61
sql/sql_show.cc
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@ -1108,8 +1108,35 @@ static void append_directory(THD *thd, String *packet, const char *dir_type,
#define LIST_PROCESS_HOST_LEN 64
static bool get_field_default_value(THD *thd, Field *timestamp_field,
Field *field, String *def_value,
/**
Print "ON UPDATE" clause of a field into a string.
@param timestamp_field Pointer to timestamp field of a table.
@param field The field to generate ON UPDATE clause for.
@bool lcase Whether to print in lower case.
@return false on success, true on error.
*/
static bool print_on_update_clause(Field *field, String *val, bool lcase)
{
DBUG_ASSERT(val->charset()->mbminlen == 1);
val->length(0);
if (field->has_update_default_function())
{
if (lcase)
val->append(STRING_WITH_LEN("on update "));
else
val->append(STRING_WITH_LEN("ON UPDATE "));
val->append(STRING_WITH_LEN("CURRENT_TIMESTAMP"));
if (field->decimals() > 0)
val->append_parenthesized(field->decimals());
return true;
}
return false;
}
static bool get_field_default_value(THD *thd, Field *field, String *def_value,
bool quoted)
{
bool has_default;
@ -1120,8 +1147,7 @@ static bool get_field_default_value(THD *thd, Field *timestamp_field,
We are using CURRENT_TIMESTAMP instead of NOW because it is
more standard
*/
has_now_default= (timestamp_field == field &&
field->unireg_check != Field::TIMESTAMP_UN_FIELD);
has_now_default= field->has_insert_default_function();
has_default= (field_type != FIELD_TYPE_BLOB &&
!(field->flags & NO_DEFAULT_VALUE_FLAG) &&
@ -1133,7 +1159,11 @@ static bool get_field_default_value(THD *thd, Field *timestamp_field,
if (has_default)
{
if (has_now_default)
{
def_value->append(STRING_WITH_LEN("CURRENT_TIMESTAMP"));
if (field->decimals() > 0)
def_value->append_parenthesized(field->decimals());
}
else if (!field->is_null())
{ // Not null by default
char tmp[MAX_FIELD_WIDTH];
@ -1365,16 +1395,18 @@ int store_create_info(THD *thd, TABLE_LIST *table_list, String *packet,
}
if (!field->vcol_info &&
get_field_default_value(thd, table->timestamp_field,
field, &def_value, 1))
get_field_default_value(thd, field, &def_value, 1))
{
packet->append(STRING_WITH_LEN(" DEFAULT "));
packet->append(def_value.ptr(), def_value.length(), system_charset_info);
}
if (!limited_mysql_mode && table->timestamp_field == field &&
field->unireg_check != Field::TIMESTAMP_DN_FIELD)
packet->append(STRING_WITH_LEN(" ON UPDATE CURRENT_TIMESTAMP"));
if (!limited_mysql_mode && print_on_update_clause(field, &def_value, false))
{
packet->append(STRING_WITH_LEN(" "));
packet->append(def_value);
}
if (field->unireg_check == Field::NEXT_NUMBER &&
!(thd->variables.sql_mode & MODE_NO_FIELD_OPTIONS))
@ -4758,7 +4790,7 @@ static int get_schema_column_record(THD *thd, TABLE_LIST *tables,
const char *wild= lex->wild ? lex->wild->ptr() : NullS;
CHARSET_INFO *cs= system_charset_info;
TABLE *show_table;
Field **ptr, *field, *timestamp_field;
Field **ptr, *field;
int count;
DBUG_ENTER("get_schema_column_record");
@ -4782,7 +4814,6 @@ static int get_schema_column_record(THD *thd, TABLE_LIST *tables,
show_table= tables->table;
count= 0;
ptr= show_table->field;
timestamp_field= show_table->timestamp_field;
show_table->use_all_columns(); // Required for default
restore_record(show_table, s->default_values);
@ -4830,7 +4861,7 @@ static int get_schema_column_record(THD *thd, TABLE_LIST *tables,
cs);
table->field[4]->store((longlong) count, TRUE);
if (get_field_default_value(thd, timestamp_field, field, &type, 0))
if (get_field_default_value(thd, field, &type, 0))
{
table->field[5]->store(type.ptr(), type.length(), cs);
table->field[5]->set_notnull();
@ -4847,10 +4878,8 @@ static int get_schema_column_record(THD *thd, TABLE_LIST *tables,
if (field->unireg_check == Field::NEXT_NUMBER)
table->field[17]->store(STRING_WITH_LEN("auto_increment"), cs);
if (timestamp_field == field &&
field->unireg_check != Field::TIMESTAMP_DN_FIELD)
table->field[17]->store(STRING_WITH_LEN("on update CURRENT_TIMESTAMP"),
cs);
if (print_on_update_clause(field, &type, true))
table->field[17]->store(type.ptr(), type.length(), cs);
if (field->vcol_info)
{
if (field->stored_in_db)